Variable speed electric power unit



April 30, 1940. D. HEYER ET'AL 2,198,940

VARIABLE SPEED ELECTRIC POWER UNIT K Filednarcn e. 19:53 l y4 sheets-sheet 1 INVENTORS ATTORNEY y April 3.0,V '1940.

VARIABLE SPEED EIQEC'KIRIC POWER UNIT Filed March e, 1955 f 4 Sheets-Sheet 2 -||||ll l' Hmmm.

NVENTORS MEYER' Em 2.198.940

April 3o, 1940. D. HEYE'RgE-m E 2,198,940`

VARIABLE SPEED ELECTRIC EOWER yUNIT Filed March 6, k1933 4 YSheelLS--Sheefl'l 5 l l INVENTOR. onfgezaf/ U ATTORNEY.

April 30, v1940. D. HEYER Er Al.

VARIABLE SPEED ELECTRIC POWER UNIT Filed March e. 1933 4 `sheve'cesneet 4 I mi von. y. 31W m L Mm I ,v ,n m., SW m 7 A eog'gelQ/Ze ew Patented Apr. 3o, 1940 2,198,940

UNITED STATES PATENT OFFICE 2.198.940 VARIABLE SPEED ELECTRIC rowEa UNIT Don Heyer and George T. Pfleger, Los Angeles, Calif., assignors to U. S. Electrical Motors, Inc., a corporation of California Application March 6, 1933, Serial No. 659,684 8 Claims. (Cl. 'I4-230.17)

This invention relates to an electric motor ments used for indicating the speed of the unit drive, and more particularly to an. adjustable for any adjustment.

transmission mechanism whereby the drive ratio An electric motor I (Fig. 1) is shown as mountfrom the motor to the load can be varied through ed in an enclosed casing 2. This casing has a small increments. protruding shaft 3 which may be appropriately 5 This is accomplished by the aid of pulley struccoupled to a load. This shaft 3 is arranged to tures, the effective diameters of which can be be driven from the motor shaft, as by the aid varied. Each pulley structure can comprise a of a rflexible belt 4 which can engage an adjustpair of pulley sections movable with respect to able pulley structure 5, carried by shaft 3. each other in an axial direction, and each having 'I'his adjustable pulley structure comprises two 10 a belt-engaging face that is sloping. Thus as the relatively movable sections 6 and 1. One secsloping faces approach each other, the flexible tion, such as 6, may be firmly fixed to shaft 3, belt engaging the faces moves outwardly and the as by set screw 8; and the other section 1 may f effective pulley diameter is increased. Conversebe splined to shaft 3, Ato permit axial movement 1y, when the sloping faces recede from each thereof with respect to the shaft and with vre- 1I other, the flexible belt is permitted to move in- .spect to the other section 6. Since the opposed wardly, and the effective pulley diameter is defaces of these pulley sections are inclined,l it is creased, apparent that axial adjustment of pulley section It is one of the objects of this invention to 1 causes a corresponding variation of the eecprovide a simple and compact electric power unit tive pulley diameter. Thus in the position shown )n in which the speed variations can be eillcaciously in Fig.V 1, the opposed sloping faces are brought secured. y as close together as permissible, and, therefore,

It is another object of the invention to make the effective pulley diameter is a maximuml By it possible to control the variable pulley strucmoving the adjustable section 1 toward the right,

.ture from'a remote point, and particularly by the the sloping faces separate, permitting the V-belt 25 aid of fluid pressure. 4 to move closer to the axis of shaft 3, whereby This invention possesses many other advanthe effective pulley diameter is reduced.

tages, and has other objects which may be made It is to be understood, of course, that belt more easily apparent from a consideration of 4 may pass around a similar pulley structure fasseveral embodiments of the invention. For this tened to the shaft of motor l, and this pulley 3o purpose there is shown a few forms in the drawstructure, so fastened to the shaft 43 of motor ings accompanying and forming part of the presl, is arranged automatically to take up the belt ent specification. These forms shall now be deslack as is well understood; for example, by the scribed in detail, illustrating the general prinaid of a resilient force urging the pulley secciples of the invention; but it is to be undertions together. One form of such a mechanism 35 stood that this detailed description is not to .be is disclosed in the application filed September 2, taken in a limiting sense, since the scope of the 1932, in the name of Don Heyer, Serial No. invention is best defined by the appended claims. 631,533, and entitled Variable speed transmis- Referring to the drawings: sion device.

Figure 1 is a plan view of a power unit em- 'I'hus on motor shaft 43 is fixed a hollow ex- 0 bodying the invention; the pulley structure, the tension 44. On this extension is a fixed pulley remote control device, and the motor casing besection 45. 'Ihe movable pulley section 46 is sliding shown in section; able over the extension 44, and is constrained Figs. 2 and 3 are sectional views of modicaagainst rotation relative to the shaft as by a pin tions of the remote control device; 41 passing through slots 48 in the extension 44 45 Fig. 4 is a diagram, mainly in section, of a and fastened to the hub of section 46. A comform of the invention in which two adjustable pression spring 49 is enclosed in extension 44 and pulley structures, joined by a Aflexible belt, are acts against the pin 41 to urge it toward the controlled by fluid pressure; right in slots 48. This spring thus urges pulley Fig.. 5 is an enlarged view showing a system section 46 toward section 45 to keep them both 50 similar to Fig, 1, but with an arrangement forI in frictional engagement with belt 4.

compensating for losses of fluid or for belt wear; The manner in which shaft 3 is supported and Fig. 6 is a detail end view, taken from plane in which pulley section 1 is adjusted will now be 6-6 of Fig. 5; and described. Thus the left hand end of the shaft Fig. 'l is an enlarged detail of one of the ele- 3 has a shoulder 9 against which the inner race u of a thrust ball bearing structure I0 is driven. The outer race is held in the inner surface at an aperture in the casing 2, as by the aid of exterior and interior caps II and l2 respectively.

'I'he adjustable pulley section 1 has a hub on which is firmly fixed the inner race of a set of thrust ball bearings I3. The outer race of this ball bearing structure is accommodated in an axially movable member I4. It is thus apparent that since the hub of adjustable section 1 is accommodated in a bearing structure adjacent the right hand end of shaft 3, this shaft 3 is effectively supported at both ends. If desired, a cap I5 fastened to the left hand end of the movable member I4 can be used to maintain the ball bearing I3 in place.

It is apparent that member I4, if moved in a direction that is axial with respect to shaft 3, will perform the function of adjusting the effective pulley diameter. This is due to the fact thatl axial movement.A of this member will cause a corresponding axial movement of the adjustable pulley section 1. The manner in which this member I4 is moved will now be described.

Member I4 forms one wall of a closed variable volume liquid chamber I6. The position of the member I4 can be determined by the amount of fluid such as oil in chamber I5. If the quantity of liquid increases, the wall 42 moves to the left, If the quantity is decreased, the wall 42 is moved to the rightby the pressure of the belt 4 against the face of the movable pulley section 1. The quantity of this liquid is determined from a remote station, as by the aid of a second variable volume liquid chamber I1 connected to the chamber I6 as by a connection 18. 'I'his connection I8 can be. a flexible tube, and is indicated as of indefinite length. way, the variable volume chamber I1 can be at a place remote from the power unit, and in any convenient location for manual operation.

In the present instance, the variable volume chambers I6 and I1 are formed as by cylinders and pistons. Thus the movable member I4 can form the piston 42, which is the movable wall of the cylinder member I9. The packing or other means by which member I4 is maintained in fluid tight relation to cylinder I9 also suiices to hold the member against rotation. The only force tending to cause such rotation is that transmitted from shaft 3 through bearing I3, and since this force is very slight, the friction of the packing means readily overcomes it. This cylinder can be supported as by the aid of a flange 2U attached to the wall of the casing 2.

Similarly, variable volume chamber I1 can comprise a cylinder member 2|, having a cap or cover 22. Inside of cylinder 2I is a piston structure 23, fastened to a stem 24, passing through the cap 22. Stem 24 is constrained against rotation with respect to the cylinder 2|. Axial adjustment of the stem 24 thus correspondingly adjusts the volume of cylinder space I1. For t'he position shown in Fig. 1, this cylinder space is a minimum, while the cylinder space I6 is a maximum.

Since the volume of liquid in the chambers I6--I1 and connection I8 is constant, it is apparent that when piston 23 is moved toward the right, piston member I4 must move correspondingly to the right in order to readjust the combined volume of the chambers I6-I1 and I8. This movement of the piston 42 toward the right is produced by the pressure of the belt 4 against the face of pulley section` 1, as the oil In this vdescribed in connection with Fig. 1.

recedes from chamber I8 to follow the movement of piston ,23. Conversely, motion of piston 23 toward the left will pass'the liquid through connection I8, and will operate the piston 42 toward the left by fluid pressure.

An adjustable stop 43' can be provided, such as a screw or bolt, to limit movement of piston 42 toward the right.

Any appropriate means may be utilized to produce the motion of piston 23 for adjusting the volume of the space I1. In the present instance, there is shown a hand wheel 25 journalled in a stationary wall 26 and having a threaded stem 21. This stem 21 engages the internal threads provided in the stem 24. Rotation of hand wheel 25 thus causes a corresponding axial movement of the stem 24, which is constrained as heretofore mentioned, against rotation.

'I'he hand wheel 25 may be located at any convenient place for manipulation by an operator; and it may be combined with any appropriate indicator for showing the resulting speed attained by shaft 3.

In Fig. 2, the variable volume chambers are formed in a different way. Thus the chamber 28 is in the form of a metal bellows having a tubular corrugated Wall which is collapsible. The end walls 29 and 30 are rigid, and wall 29 is fixed. Wall 30 may be connected to the adjusted pulley section.

The other variable volume chamber is formed by a similar metal bellows 3I, having a iixed end wall` 32 and a movable end wall 33. This end wall 33 carries a flanged nut 34 constrained from rotation and engaged by the threaded stem 35 of the hand wheel 36.

The mode of operation of this form of the invention is substantially the same as that just Movement of the wall 33 toward the right causes a reduction in the volume of the metal bellows and a corresponding increase in volume of the metal bellows 28. Wall 30 will then move toward the right and will effect the speed adjustment.

In the form shown in Fig. 3, the hand wheel 36 and stem 35 vare arranged as in Fig. 1. Cap 22 and piston 23 are arranged to vary the volume of cylinder space 31. This cylinder space is connected as by flexible connection I8 to the space 38. This adjustable volume chamber 3l is formed by the aid of a cylinder 39 and a movable piston 40. In this form the movable piston 4II carries a stem 4I which is mechanically connected to the adjustable pulley section to operate it.:

In the form thus far described the adjustment for variable speed is accomplished by varying the effective diameter of one of aipair of variable pulley structures. The other one of the pair of pulleys in the transmission is arranged, as by the aid of a spring 49 (Fig. l) to conform to the adjusted position of the other pulley structure. It is apparent, however, that a fluid control for positive adjustment could be used for pulley structure 45-46 of Fig. 1, which may be entirely similar to the fluid control-'mechanism used in connection with the pulley structure 5. In such an arrangement another variable volume chamber is utilized, such as I6 (Fig. 1) for moving pulley section 46 from a remote control point.

One elaboration of such a system is indicated in Fig. 4, in which a common manual control is provided for the two pulley structures.- In this figure the transmission mechanism is housed in a casing 50. As before, an electric motor 5| can be supported in an aperture in the casing, and can drivea shaft 52. The driven shaft 53 projects out of the casing 50 for appropriate connection to a load.

As in the form of the invention first described, both shafts 52 and 53 carry variable pulley structures such as 54 and 55. Variable pulley structure 54 includes the section 55 fixed against axial movement, as by screw 51 passing through the hub of this section, and engaging shaft 52. 'I'he movable section 58 is arranged for axial movement on shaft 52, as by being splined thereto. The hub 59 of this section is supported as by the aid of ball bearings 60 on the inside of axially movable support 5|. This support is guided in a slot in the hollow cap structure 62 as by the aid of a key 53 fastened to the member 6|.

The end of shaft 52 may be hollow, and the outer race of bearings 50 can be held in place as by a removable dust proof cover |00. Bolts |0|, passing through the support 6| can be used to hold this cover in place.

Similarly, the driven pulleystructure 55 has a section 64 fixed to the shaft 53. The adjustable pulley section 55 is supported for adjustment in right will cause simultaneous reduction in the effective diameter of pulley structure 54, and a corresponding increase in the effective diameter of the pulley structure 55.

Simultaneous adjustment of the pulley sections 58 and 65 can be secured as'by the aid of a plurality of piston and cylinder mechanisms such as disclosed in Fig. 1, or by any other appropriate fluid control mechanism involving variable or adjustable volume iiuid chambers. In the present instance there are shown metal bellows structures, capable of compression and expansion, for forming the variable or adjustable volume chambers.

Thus for example, to the cover |02 of vcap 62 can be fastened the stationary wall 69 of a metal bellows structure 10. The movable wall 1| of this bellows 10 is arranged to move the support 6| upon an expansion and contraction of the bellows. Instead of a direct mechanical connection between the walls 1| and the support 5|, there is preferably included a compression spring 12 seated in a reentrant portion of the wall 1|. The lower end of this spring seats on the wall 1 I, and its upper end/"telescopes over a spring guiding boss 13. Th spring 12 is strong enough to take up belt wear or slack, by urging the removable section 58 resiliently into contact with the belt 4. The strength of the spring is designed for this purpose, as well as to provide suiiicient frictional force between the pulley structure and the flexible belt to transmit the mechanical load.

In this way, the wall 1|, in conjunction with the adjacent surface of member 6|, serves as a limit for the separating action of the section 54 when a heavy load is imposed upon the device. Thus these surfaces may abut temporarily, as when there is a. heavy starting torque. For norvmal operation, spring 12 is strong enough toy separate the surfaces byy urging the bearing support member 6| to the relative position shown.

The cover |02 for cap 62 is similar in structure to cover |02 shown in Figs. 5 and 6, and in connection with member 58. Thus this cover can have a right angled port |03 leading to a connection nipple |04. In order to make it possible to fill the bellows 10 prior to installation, and

prior to coupling to a connection 15 leading to a remote control adjustable volume fluid chamber, there is provided a closure |05 adapted to cooperate with the end of port |03, optionally to interrupt the passage to nipple |04.

For this purpose, closure |05 is threaded into a boss |08, as by the aid of a screw driver slot |01, and it can be screwed down so that a leather closure washer ||0 may be urged tightly over the end of port |03. However, in normal operation, the member |05 isleft raised off its seat, as shown clearly in Fig. 5.

Further to ensure against unauthorized or inadvertent variation in the position of member |05, as well as to ensure further against leaks, a supplemental cap |08 can be screwed tightly over boss |06. It is also noted in Fig. 5 that the inner wall |09 of cap |02 is inclined. Thus when the entire bellows structure is being filled through nipple |04 the air being displaced by the oil is guided'by this slanting wall to escape out of the vstructure withoutdanger of being trapped.

After complete filling, the closure member |05 is screwed down, and the bellows structure can be shipped to the location where the unit is to be assembled.A There the connection 15 is coupled to nipple |04, and the mechanism placed in condition for operation in a manner to be described in detail hereinafter.

The volume of'bellows 10 can be controlled from'a remote point, as by the aid of an adjustable volume chamber formed by a metal bellows 14. The interior of this metal bellows is connected by 'conduit 15 (shown as of indefinite length) with the interior of bellows 10, through nipple |04. One wall 16 of bellows 14 is stationary, while the other wall 11 is movable. Wall 16 can be in the form of a cover having a construction similar to the other covers |02, by the aid of which the filling and shipment of bellows 14 are facilitated.

Ifthe metal bellows 10 and 14 with their connections 15 be filled with an incompressible fluid, such as oil,l it is apparent that an adjustment in the volume of bellows 14 causes a corresponding opposite variation in volume of bellows 10. Accordingly, the movable wall 1| will move either to the right or left, causing adjustable pulley section 58 to assume its desired position. v

A substantially similar control system is utilized in connection with the movable support 61 of pulley structure 55. In this case there is a bellows-18 and a compression spring 19 interposed between it and support 61. An adjustable volumeI chamber is formed by the metal bellows 80. This metal bellows has a stationary wall 8| and a movable wall 82. The interior of bellows is connected to the interior of bellows 18 through the conduit 83. The two fluid systems for the two pulley structures are isolated from each other; but the two movable walls 11 and 82 can be mechanically joined, as by a rod 84. Movement of the rod in one or the other direction causes a reduction in volume of one bellows and an increase in volume of the other bellows, whereby proper movements of adjustable pulley sections 58 and 65 are secured. A hand lever 85 can be joined as by a slot and pin connection 81 to the connecting rod 84 for simultaneous adjustment of the volumes of bellows I4 and 80. The position of the lever 85 can be maintained as by a common form of latch mechanism, including a segment bar 88.

Provisions are made for setting the volume of each of the fluid spaces, to ensure that both fluid systems may operate the respective movable sections 58 and 65 in proper synchronized action. Such setting may be necessitated, for example, due to slight oil leaks in service, or belt wear.

For this purpose, the movable walls 1l and 82 are respectively joined to rod 8G by adjustable connections 89, 90. These can be in the form of studs having right and left hand threads at their extremities, engaging respectively in threaded apertures in the rod 84 and walls ll, 82. Thus by turning either of these studs as by the aid of squared portions Si, the movable walls 'Il and e2 can be setto take up slack. After such setting, a check nut 92 can be tightened against the movable wall to hold the setting against accidental variation.

This setting is probably accomplished at rather infrequent intervals, such as once a month or longer period. In order to ensure that sufficient oil will always be available, each system is provided with a comparatively `large container d3, tl, which can be lled for example at still more infrequent intervals, such as annually. These containers are in communication with connections 15 and 83 respectively.

In operating the system shown in Fig. 4, it is apparent that the sett-ing of the effective pulley diameters can take place even while the apparatus is stationary. Thus for example, in the position shown, bellows 'i8 can be expanded within the limits of the clearance between the bellows and support El; and correspondingly, bellows l@ for the pulley structure 54 is contracted, permitting spring l2 to expand. Belt ii, being disposed between the sections Ell, 65, prevents these sections from moving toward each other while the apparatus is stationary. However, as soon as the motor 5| is operated, the belt il moves outwardly to correspond to the presettihg. By increasing the clearance between the bellows structures 70, T8, and the supports 5|, Si?, this presetting during standstill can be accomplished for a substantial range of pulley diameters.

The advantage of this mode of operation is that the motor 5| can be set for low speed operation of the load shaft 53 even before the motor is started.

The manner in which the power unit can be installed will now be described. The bellows l0, lil, "it and 30 can be filled and closed as heretofore described, prior to shipment of the unit, the connections 15 and 83 being unconnected to their respective bellows. After properly setting up the machine and the manual control, the connections l5, 83 are threaded into the nipples |04. With the bellows still closed, containers 93, 94 are filled. Since both fluid systems are similar, the description will proceed with system ll 5 @iii-mld.

Air will be trapped between the oil flowing from reservoir t3 and each of the bellows l0, i4. To allow this air to escape, a screw 95 (Fig. 5) is removed from nipple im to form an air vent. The air escapes and oil will overflow. This overflowing oil is prevented from flowing down cover tilt by annular grooves t leading to a drain tip 2li on the lower side of nipple itil. Then plug 55 is replaced, and container 93 is refilled, and closed by plug 98. Now cap |08 can be removed, and closure valve |05 retracted to place the bellows in communication with connection 15. steps are taken to vent the air between container 93 and bellows 10.

In the form of the invention shown in Fig; 4, the volumes of the two fluid systems, including respectively, metal bellows l0, 14 and the metal bellows T8, 80 can be set by varying the position of one of the walls in the metal bellows. This setting of the volume can be accomplished, however, in other ways.

For example, in the form of the invention shown in Figs. 5, 6, and 7, a fluid control system is indicated in which use is made of an adjustable volume metal bellows This metal bellows is coupled by a connection H2 to a variable volume mechanism |13 acting on a movable pulley section. The metal bellows has its right hand end fastened, as by soldering, to the cover member |02. This cover member, as described in connection with Fig. 4, carries the closure member H15, as well as the nipple if for facilitating connection to the device i i3.

In order to house the adjustable bellows properly, use is made of a stationary casing ||4, in which the bellows iii is accommodated. 'Ihis stationary casing can be supported on any appropriate stationary surface, as by the aid of a flange ||5.

The left hand end of the bellows |i| is joined as by soldering, to a plate ||6. This plate abuts against the inner surface of an axially movable member i Il, but need not be joined thereto. This member Hl is slidable inside of casing ||4, and is provided with a deep flange ||8 to guide it properly inside of the casing. 'I'he plate IIB, which is annular in form, is passed over the hub of the member Ill, and ts between this hub and the flange H8. In order to prevent rotation of member Ill within the casing H4, use may be made of a spline construction. Thus a key |9 can be carried by member at its outer periphery slidable in a keyway |20 on the inner wall of the casing ||4. v

It is apparent that movement of member to the right will compress the bellows and conversely, movement of member lll to the left will expand the bellows This axial motion of member ||1 is accomplished in the present instance by the aid of a shaft |2|. 'I'his shaft is rotatable as bfy a hand wheel |22 securely fastened thereon, as by a key |53. The shaft furthermore has an enlarged threaded fportion |23 engaging in corresponding threads in the hub of member 1. The shaft |2| passes through a clearance aperture in the boss |24 of casing ||4. It is restrained against axial movement by the hub of wheel |22, contacting with the left hand surface of the boss |24, as well as by a thrust bearing |25 located between a shoulder at the left hand end of the enlarged threaded portion |23, and the inner side of the casing H4. It is thus apparent that as hand wheel |22 is turned, the bellows can be adjusted.

To form a closed chamber |26 inside of bellows lll, there is provided in the present instance a supplemental or auxiliary metallic bellows |2l, which is reentrant with respect to the bellows The left hand end of the inner bellows i2l is securely fastened to the plate I6, as by soldering. Its right hand end is similarly Similar fastened to a disc |28, forming an imperforate wall. It is thus seen that the effective volume of the bellows mechanism ||||21 includes the annular space between the two bellows as well as the space between the members |28 and |02. In ordinary operation, the disc |28 is moved axially in exact synchronism with the motion of member ||1; that is, bellows |21 is not collapsed or expanded during normal operation of adjusting the speed, all of the volume variation taking place solely by virtue of the fact that member ||1 approaches cover |02.

To provide this synchronous motion of disc |28 with member ||1, this disc |28 is provided with a tapped boss |28. In this boss is engaged the threaded end |30 of a shaft |3|. This shaft |3| is accommodated inside of shaft |2|, which is made hollow for this purpose. The pitches of the threads on shafts |2| and |3| are exactly the same; so that when shafts |2| and |3| are locked together for rotation, the disc |28 is advanced on portion |30 at the same rate as member ||1 is advanced on portion |23. Therefore, the distance between these two elements I1 and |28 remains constant while the two shafts |2| and |3| are rotated in unison.

This rotation in unison is accomplished by fastening shaft |3| within shaft |2|, as for example by the aid of a wing nut |32.' This wing nut engages the threaded reduced end |33 of the shaft |3|. This wing nut presses against a small hand wheel |34 fastened to shaft |3|, and thereby pulls the shoulder |35 on shaft |3| against a corresponding internal shoulder in the exterior shaft |2I. It is apparent that as long as the nut |32 is tight, shaft |3| is held frctionally against rotation in shaft |2|. Therefore, rotation of' hand Wheel |22 acts to rotate both of these shafts, and accordingly members ||1 and |28 are moved in unison.

Now should it be desired to set the volume of space |28 to take up for loss in liquid or for belt wear, it is possible to do this by moving disc |28 with respect to member ||1, thereby expanding or contracting bellows |21. `To accomplish this result, wing nut |32 is loosened. Then while hand wheel |22 is held stationary, the hand wheel |34 can be rotated to rotate shaft |3| with respect to shaft |2|. This relative rotation causes bellows |21 to be expanded or contracted as desired. After the adjustment is completed, wing nut |32 can be tightened and the two shafts |2| and |3| held together against relative rotation.

It is also possible to provide an effective speed indicator, which responds to the axial position of member ||1. This member can be provided with a transverse pin |35 supported onl a rib |36.

A rotatable lever |31 (Figs. 5 and 7) is mounted on a pivot screw |38. This pivot screw |38 is supported on an upstanding rib |40 provided in a slotted cover |4`| for casing ||4. A helical spring |39 acts to urge the pivoted lever |31 resilient against the pin |35 so that this lever |31 follows the position of the pin. The lower end of the lever, passing through cover |4|, carries a pointer mechanism |42, cooperating with an arcuate scale |43 supported on a bracket |44.

In order to adjust the pointer |42 for calibration purposes, lever |31 is not permanently joined to the pointer |42. Instead, this pointer |42 overlies the lever |31 and is pivoted on the'pivot pin |38.v An adjusting screw |4'5 passes through an arcuate slot |46 in the pointer |42, and engages a threaded aperture at the extremity of the lever |31. It is thus apparent that by loosening the adjusting screw'l45, the pointer |42 can be moved angularly on its pivot with respect to lever |31, within the limits prescribed by the arcuate slot |46. Thus the pointer |42 can be moved without disturbing the position of lever |31, and can be held in any adjusted position by tightening the screw |45, holding the pointer |42 and lever |31 together.

In this form of the mechanism also, a container 83 can be inserted in the connection ||2 to provide a convenient mode for filling the system.

In order to impose limits upon the axial movement of member ||1, use can be made of adjustable abutments |41 and |48. Each of these is in the form of a threaded stud extending in an axial direction and adapted respectively to cooperate with a boss |49 on member ||1, and with the edge of flange H8. In the position shown the bellows is in fully expanded position, the abutment |41 engaging the boss |48. Upon movement of member ||1 toward the right, ultimately the abutment |48 will be engaged by the flange |l8.

The abutments |41 and |48 may be threaded into threaded apertures in the casing ||4 and in the cover |02. They may be held in adjusted position by the aid of lock nuts |50 and |5|.

Preferably also, an air vent |52 can be provided through the member ||1 to permit air to escape or enter to the inside of auxiliary bellows |21. f

We claim:

1. In a variable transmission device incorporating two adjustable pulley structures, each structure having a `pair of relatively axially adjustable pulley sections, each of the sections having inclined belt engaging faces, whereby relative axial adjustment of the sections produces a corresponding variation in effective pulley diameters, the combination therewith of means for-simultaneously increasing the effective diameter of one pulley structure and decreasing the effective diameter of the other pulley structure, comprising a pair of means, each forming a variable volume fluid chamber, respectively cooperating with said pulley structures to cause relative movement between the pulley sections, means for simultaneously varying said volumes, and means exerting a resilient force interposed between each variable volume chamber and the corresponding pulley structure.

2. In a variable transmission device incorporating two adjustable pulley structures, each structure having a pair of relatively axially adjustable pulley sections, each of the sections having inclined belt engaging faces, whereby relative axial adjustment of the sections produces a corresponding variation in effective pulley diameters, the combination therewith of means for simultaneously increasing the effective diameter of one pulley structure and decreasing the effective diameter of the other pulley structure, comprising a pair of means, each forming a variable volume fluid chamber, respectively cooperating with said pulley structures to cause relative movement between the pulley sections, a pair of means, each forming an adjustable volume fluid chamber, respectively connected to the variable volume chambers, and means for simultaneously adjusting said adjustable volume chambers, and a pair of reservoirs respectively joined to the connections for passing fluid to the chambers.

3. Ina variable transmission device incorporating two adjustable pulley structures, each structure having a pair ofrelatively axially adjustablefpulley sections, each of the sections having inclined belt engaging faces, whereby relative axial adjustment of the sections produces a corresponding variation in effective pulley diameters, the combination therewith of means for simultaneously increasing the eiective diameter of one pulley structure and decreasing the effective diameter of the other pulley structure, comprising a pair of metallic bellows, respectively cooperating with the pulley structures, a compression spring interposed between each bellows and its corresponding pulley structure, and fluid pressure means for simultaneously and compensatingly adjusting the volumes of said bellows.

4. In a variable speed drive, a shaft, means for rotatably supporting one end of said shaft and for restricting axial movement thereof, an adjustable pulley structure in axial driving relation to said shaft, said adjustable pulley structure having a pair of pulley sections with opp'osed inclined belt engaging faces forming by relative axial adjustment variable effective pulley diameters, a hub provided for one of said pulley sections, an axially adjustable member forming a bearing support for said hub and the shaft associated with said pulley structure, a stationary means for slidably supporting said axially adjustable member and for preventing rotation thereof, and iluid pressure means for adjusting the axial position of said axially adjustable member.

5. In a variable diameter pulley structure, a pair of relatively axially adjustable pulley sections having inclined faces, forming by adjustment variable effective pulley diameters, an axially movable member for adjusting and supporting one of said pulley sections, a mechanically adjustable member, a resilient connection between the axially movable member and the mechanically adjustable member, and means for restricting rotation of said axially movable member.

6. In yan adjustable pulley structure having a pair of relatively axially adjustable pulley sections, each of the sections having inclined belt engaging faces, whereby relative axial adjustment of the sections produces a corresponding variation in effective pulley diameters, the combination therewith of a bearing axially fixed with respect to one of said pulley sections and serving to support said one section, an axially movableA member engaging said bearing for supporting it as well as for adjusting the axial position of said pulley section, an axially movable adjusting means,` and a resilient connection between the axially movable member and the axially movable adjusting means. V

7. In a variable ratio transmission unit, a variable diameter pulley structure having a pair of relatively axially adjustable pulley sections, forming byrelative axial adjustment, variable eective pulley diameters, means forming a variable volume fluid chamber having rigid end walls and a collapsible corrugated wall joining the end walls, an axially adjustable member interposed between one of said walls and said pulley structure, a bearing structure supported on said member and engaging one of the pulley sections, said bearing structure serving to support the pulley section as well as to maintain it in fixed axial relationship with the member, means forming a mechanical connection between said member and said one end wall, whereby movement of the wall is elective to adjust the pulley section, means forming another variable volume chamber remote from said rst chamber, a connection between the two chambers, and means for varying the volume of said other chamber.

8. In a variable ratio transmission unit, a variable diameter pulley structure having a pair of relatively axially adjustable pulley sections, forming by relative axial adjustment variable effective pulley diameters, a non-rotary member supported for axial movement with respect to the pulley structure; a bearing structure supported by said member and engaging one of the pulley sections, said structure being adapted to support the pulley section with respect to the member as well as to maintain it in xed axial relationship therewith, means forming a variable volume fluid chamber having a movable wall, means forming a mechanical connection between the member and the Wall, whereby movement of the wall is effective to cause movement of the member, and means to alter the volume of said chamber.

DON HEYER, GEORGE T. PFLEGER. 

